Georg lucas



UNITED STATES PATENT OFFICE.

GEORG LUCAS, OF BERLIN, GERMANY.

SCAFFOLD.

SPECIFICATION forming part of Letters Patent No. 561,263, dated June 2,1896. 7 Application filed December 14, 1895. Serial No. 572,172. (Nomodel.)

To all whom, it may concern:

Be it known that I, GEORG LUCAS, painter, of No. 7 Fischerstrasse,Berlin, in the Empire of Germany, have invented an Improvement inscaffolds; and I do hereby declare the nature of this invention and inwhat manner the same is to be performed. to be particularly describedand ascertained in and by the following statement.

This invention relates to a screw block or holdfast for securing boardsor planks to the side rails or uprights of ladders for the purpose oferecting scaffoldings for painters, decorators, and other operativesemployed in the building trade as a substitute for the scaffoldingtrestles or jacks now generally used. By means of the improved holdfaststwo or more ladders may be connected by planks in such a manner thatafter these planks have been covered over with the necessary boards ascaffolding of considerable stability and strength is obtained as aresult.

In the accompanying drawings, Figure 1 is a scaffolding erected with theassistance of my improved screw-holdfasts. Fig. 2 is a perspective viewof an improved screw block or holdfast. Fig. 3 is a side view of thesame as it appears when attached to the ladder. Fig. 4 is a modificationof the same, adapted for use with ladders having half-circular sectionside rails or uprights.

The improved screw block or holdfast, which may be made of wrought-iron,caststeel, or the like, consists of a clamp a, which carries in itsfront part a screw 6, preferably fitted at its forward end with a clawor hook. The rear portion Zof the clamp a is secured to the side rail bymeans of two screws 61, one each side of the side rail, and havingthumbnuts 0 screwed onto them and through the medium of an angle pieceor shoe 1). The anglepiece I) is placed against one of the rungs of theladder h, so that the clamp cannot slip off. In order to prevent anylateral displacement, another clamp 70 should preferably be provided,which in that case is so arranged that it embraces the beam of theladder and may be firmly pressed against it by means of wooden wedges 'ior in any other convenient manner. Where the side rails of the ladderare of semicircular cross-section, the parts I and 70 should preferablybe made half-round also, as illustrated in Fig. 4 of the drawings, sothat they may correctly fit the side rail. After four or a greaternumber of such holdfasts have been screwed to the ladders on therequired level or height, planks f, placed on edge,are inserted into theclamps a and tightly compressed and secured by means of the screw e.Upon these planks or rafters flooring-boards are laid to complete thescaffolding, which when so completed will prove very reliable andconvenient. If desired, a further diagonal connection may be formed bysuitable planks or boards or cross-pieces arranged to be, like theothers, gripped by the clamps a.

Preferably the clamps a should be bent on one side in such a manner thatthe lower edge of the plank or board f which is inserted cannot shift orslide out of position.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is- 1. Screw-boldfasts for securing planks or boards to theside rails of ladders for the purpose of erecting scaffoldings; the mainfeature of such holdfasts being a clamp, such as (1., havingclamping-screws, 'such'as e, for the reception of planks or boards,suchas f, placed on edge, and a movable shoe such as b, adapted to take upits position against the rungs h of the ladders and to be securely fixedin position by means of screws such as (1, so that the side rails of theladders are firmly clamped between the shoe b and the clamp a.

2. In combination, a clamp for scaffolding adapted to ladders and thelike comprising a clamp a, to receive and hold the side rails of thescafiold, a clamp 19 connected to the clamp a and adapted to secure theclamp a to the ladder-rail and a clamp is secured to the clamp a to holdthe same from displacement at right angles to the clamp 22,substantially as described.

In witness whereof I have hereunto set my hand in presence of twowitnesses.

, GEORG LUCAS.

Witnesses:

E. SOHMATOLLER, W. HAUPT.

